Three dimensional modeling of objects typically involve measurement of data points on the surface of the object in all three dimensions. A mechanical measurement method may be employed for this purpose. In one such method, a small probe is lowered in the vertical direction until it makes contact with the surface of the object. X, Y and Z coordinates corresponding to the contact point are recorded. The probe is then raised in the vertical direction and indexed in the horizontal direction. The probe is lowered again and the process is repeated. Although this method provides accurate results, it is not generally preferred for making 3D models due to the slow speed of the process.
To overcome the speed limitations of the mechanical measurement methods, optical measurement methods may be employed. Several known optical measurement methods for creating a 3D model involve projecting a pattern image on a 3D object and measuring the distortion of the pattern image. One such method uses a projector to project multiple pattern images onto the object. The pattern images are typically either a set of sinusoidal gray scale patterns or a set of black and white patterns. The patterns vary in only one direction so that brightness measurements on a given line perpendicular to the direction of variation are consistent when the pattern image is projected on a constant color plane. A camera records photographs of the object with each of the pattern images projected onto the object. A computer estimates the 3D shape of the object by observing the deviations in brightness perpendicular to the direction of variation of pattern image. However, this method works best with a consistently colored, non-reflective, opaque surface in dim light conditions.
Thus there is a need for a method and a system for creating a three dimensional model of the object in an improved manner.